Highlights From the Archives

Looking for an easy way to ruin your band? Try this: grow up, chill out, dig in. Shed your we-use-''party''-as-a-verb reputation and rededicate yourselves to musicianship. Embrace balladry. Allow the guitarist to sing. The Red Hot Chili Peppers, now celebrating their 20th anniversary, have done all of these things. And yet somehow, the results are spectacular.

When the Red Hot Chili Peppers first found mainstream success, in 1989, they were a funk-punk band driven by Anthony Kiedis's exuberant rapping and Flea's manic slap-bass. Over the last few years, they have changed their style by changing their emphasis. After a brief hiatus, the guitarist John Frusciante rejoined the group for its 1999 album ''Californication,'' and his lucid, labyrinthine riffs helped the Red Hot Chili Peppers evolve into a mellow progressive-rock act.

On Friday night at Madison Square Garden, it looked like the same old Red Hot Chili Peppers: shirtless, sweaty, rowdy and pumping out funk vamps. But 13 years into its career, the group has learned some new tricks and has upgraded its old ones.